The present invention relates to a printing method and a printing apparatus effective for printing of a minute pattern on a liquid crystal color filter, a chip on film for mobile phones, etc.
Conventionally, as a fine printing method and a fine printing apparatus, a printing method and a printing apparatus are proposed, as disclosed in JP-A-2000-289320 and JP-A-11-198337, in which a functional resin is coated on a silicone rubber blanket, an intaglio or a printing plate is pressed against a coated surface, a resin on the pressed portion is removed from the silicone rubber blanket, and a remaining resin is transferred to a substrate.
As described in MATERIAL STAGE Vol. 3, No. 4, 2003, there is proposed a printing apparatus that laminates carbon, which inhibits ion migration, on silver wiring, which is formed by screen process printing, with screen process printing. A roll-to-roll printing technique is also disclosed, which uses PET (polyethylene terephthalate) film or the like.
Further, there is proposed a blanket possessing a material and physical properties, which are suited to printing of fine patterns with the use of an intaglio offset printing, as disclosed in JP-A-6-255280.
The prior arts propose methods of printing a fine pattern making maximum use of a feature of a silicone rubber blanket, which is excellent in ink transfer, but the methods involve a problem that it is difficult to form a thick ink film on a surface of a silicone rubber blanket and it is not possible to make printing of a fine pattern and printing of a thick film pattern compatible since not only silicone rubber, which is small in critical surface tension and poor in ink accept performance, is used for a rubber layer on a blanket surface but also ink having a small viscosity is used.
Since a rate of ink transfer from a blanket to a substrate is high but ink tends to separate due to a low wettability, there is caused a problem that it is difficult to form an ink film on a surface of a blanket.
Further, since not only silicone rubber, which is small in critical surface tension, is used for a rubber layer on a blanket surface but also a fine ink pattern is printed on a silicone rubber blanket, there is also caused a problem that an ink pattern becomes thin in line and fine line breakage is liable to occur.
Also, material property, process condition, or the like for materialization of the printing principle, such as the relationship between surface energy of a silicone rubber blanket and surface tension of ink, ink property when unused ink is removed and a desired ink pattern is printed are not clear.